Thermal management of high flux electronics using film evaporation with an enhanced fluid delivery system (FEEDS)

Abstract

The increasing power densities of electronic devices due to more compact package requirements make their thermal management a major challenge. Adequate cooling of these devices is required to increase their lifespan and maintain operational capabilities. Over the past couple of decades, microchannel heat sinks, among other solutions, have been implemented to dissipate high heat fluxes under operational parameters of practical significance. Furthermore, convective heat transfer coefficients have been increased by using a two-phase flow and by reducing the hydraulic diameters of the channels. However, this incurs an increase in pressure drop and pumping power. A novel cooling technique, film evaporation with an enhanced fluid delivery system (FEEDS), has been demonstrated to simultaneously enhance the heat transfer coefficient while minimizing the increased pressure drop and pumping power requirements. The FEEDS cooler is a manifold-microchannel system in which an array of manifolds is positioned perpendicularly on a system of parallel microchannels. In the present work, two FEEDS coolers were designed and developed to manage high heat fluxes of electronic components. The geometrical parameters of the manifolds were varied to investigate the effect of manifold parameters on thermal and hydrodynamic performances. Both single-phase and two-phase tests were performed with R-245fa refrigerant as the working fluid at different mass fluxes, and heat transfer and pressure drop performances were measured. Heat fluxes in excess of 1 kW/cm2 with a surface superheat of 38 °C and with a low-pressure drop penalty were achieved. Additionally, this FEEDS cooler showed a relatively constant heat transfer coefficient even after the optimal vapor quality was exceeded, indicating a stable liquid film.